1. Field of the Invention
This invention relates to electrically conductive organic-inorganic hybrid composites.
2. Description of the Related Art
Inherently conductive polymers (ICP's) are organic polymers with conjugated π-electronic structures in the polymer backbone. Examples of ICP's include polyaniline, polyacetylene, polypyrrole, polythiophene, poly(phenylene vinylene) and chemical modifications thereto. These polymers are potentially useful as additives in paint formulations that are used as protective organic primers and also have anti-electrostatic, electrostatic dispersion and electromagnetic shielding applications. ICP's can exist ill several reduced or oxidized (to a variable degree) states, all of which appear in de-protonated (base) or protonated (salt) forms. However, the various states and forms of the ICP's reversibly interconvert based upon the redox and/or acid-base characteristics of their environment.
ICP's, being reversibly oxidizable and reducible, interact with metal surfaces to inhibit corrosion. Inherently conductive forms of ICP'S, i.e. the salt forms, appear to be protective against corrosion in oxidative environments. In reductive, and specifically alkaline environments, conductive forms of ICPs, are converted to insulator forms thereby deteriorating the effectiveness of ICP's to inhibit corrosion. Consequently, the inherently conductive state of ICP's can not be preserved in alkaline environments which are typically present in atmospheric conditions thereby significantly limiting the use of ICP's in protective organic primers. Also, the conversion of the conductive forms of ICP's to the insulator forms decreases the electrical conductivity of the ICP's thereby diminishing the effectiveness of the ICP's when used as an anti-electrostatic component. Accordingly, a need exists for a conducting ICP that resists conversion to an insulating form when in the presence of alkaline environments. The present invention addresses this need.